Process for the conversion of carbon to alcohols

ABSTRACT

COMPRISING A MIXTURE OF SILICA AND COPPER AND THE OXIDES OF ZINC, CHROMIUM AND BORON. THE CATALYSTS ARE SUSPENDED IN A CERAMIC CONCRETE AGGREGATE, EXTENDING THE LENGTH OF THE REACTORS AND IN THE FORM OF A CYLINDRICAL REACTOR LINER AND A SMALLER, CONCENTRIC CERAMIC CYLINDER THEREWITHIN. THE SECOND STEP IS PERFORMED IN TWO REACTORS IN SERIES.   A PROCESS FOR THE PREPARATION OF ALCOHOLS FROM PURIFIED CARBON, INCLUDING THE STEP OF HYDROGENATING THE CARBON AT HIGH TEMPERATURE AND PRESSURE IN A CATALYTIC REACTOR IN A DISPERSION WITH NAPHTHALENE AND IN THE PRESENCE OF A CATALYST COMPRISING NICKEL, RUTHENIUM, ALUMINUM AND COBALT MOLYBDATE, AND THE STEP OF OXIDIZING THE RESULTING PARAFFINS BY CONTACT WITH STEAM AT HIGH TEMPERATURE AND PRESSURE IN A CATALYTIC REACTOR IN THE PRESENCE OF A CATALYST

A. E. VELOSO 3,819,724

PROCESS FOR THE CONVERSION OF CARBON TO ALCOHOLS I June 25, 1974 FiledOct. 20. 1970 EohE 023 590 moB m mm mDQmME km wJOIOQ E 0m EEDA WJOIOU EN 1964mm mm 4 mm N 58%;:

QN ,QN PDn z mZM ZIPInEZ ZOmm 0 //vv. 5/vr0/? ALBERTO E. VELOSO B WWWUnited States Patent O US. Cl. 260-632 CB 2 Claims ABSTRACT OF THEDISCLOSURE A process for the preparation of alcohols from purifiedcarbon, including the step of hydrogenating the carbon at hightemperature and pressure in a catalytic reactor in a dispersion withnaphthalene and in the presence of a catalyst comprising nickel,ruthenium, aluminum and cobalt molybdate, and the step of oxidizing theresulting parafiins by contact with steam at high temperature andpressure in a catalytic reactor in the presence of a catalyst comprisinga mixture of silica and copper and the oxides of zinc, chromium andboron. The catalysts are suspended in a ceramic concrete aggregate,extending the length of the reactors and in the form of a cylindricalreactor liner and a smaller, concentric ceramic cylinder therewithin.The second step is performed in two reactors in series.

BACKGROUND OF THE INVENTION The field of this invention is thepreparation of alcohols by the two-step process of hydrogenatingpurified carbon to form a mixture of parafiins, and of oxidizing theparafiins to 'form their respective alcohols.

Alcohols have been proposed for use as motor fuels. Their primaryadvantage is that their exhaust products contain little or nopollutants, being substantially completely carbon dioxide and water.There is, however, no practical, large-scale process suitable for thepreparation of alcohol that is competitive with the traditional sourcesof motor fuel. It is, therefore, the major objective of this inventionto provide a process for the preparation of alcohols of sufiicientquantity to be competitive with conventional petroleum-based motorfuels.

In the present pro'cess, alcohols are synthesized from coal, or anothersource of purified carbon. The purified carbon may be obtained fromcharcoal, coal or a vegetable carbon source, for example, by the processdescribed in my patent application, Ser. No. 82,549, filed Oct. 20, 1970now US. Pat. No. 3,689,233, entitled Process for the Manufacture of HardAshless Charcoal Briquettes. Said purified carbon, as disclosed atcolumn 4, lines 30- 63 of said patent, is material which issubstantially pure ashless, comprising essentially 99.75 percent carbon.It is then a further objective to provide a process for the preparationof alcohols from a readily available source of carbon, such as coal.

The well-known Bergius process converted powdered coal and heavy oil tohydrocarbons, by catalytic hydrogenation. It is a further objective ofthis invention to provide an improved method of hydrogenating a carbonsource, as Well as to oxidize the resulting hydrocarbons to alcohols.

SUMMARY OF THE INVENTION In the present process, purified carbon ishydrogenated in the presence of a catalyst compound of about 15-20percent nickel, 15-20 percent cobalt molybdate, 15-20 percent ruthenium,and 45-55 percent aluminum, at a temperature of about 500-1500 C. and apressure of about f100-3000 atm. The resulting hydrocarbons, primarilyparafiins are oxidized in a second catalytic reactor 3,819,724 PatentedJune 25, 1974 Ice with steam in the presence of a catalyst comprised ofabout 5-10 percent zinc oxide, 2-5 percent copper, 20- 25 percentchromium oxide, 20-25 percent silica, 20-25 percent potassium oxide and20-25 percent boric oxide, at about 300-550 C. and 400-500 atm., to formthe corresponding alcohols.

The two reactors contain two concentric, porous ceramic cylindersimpregnated with the catalyst composition. The hydrogenation reactor isheated by an external, concentric furnace, which also serves to heat thesteam employed in the oxidation reactor. A third reactondistillingretort, which serves to complete the oxidation to alcohols and todistill the product, is of special construction.

BRIEF DESCRIPTION OF THE DRAWING The drawing shows schematically theequipment suitable for carrying out the present process, including ahydrogenation reactor, an oxidation reactor, and a reactordistillingretort.

DETAILED DESCRIPTION OF THE INVENTION The raw material of the presentinvention is ashless or purified carbon which may be obtained by anysuitable process, such as the method of preparing ashless vegetableblack disclosed in my concurrently filed application, Ser. No. 82,549.In the first step of the process,

the purified carbon is catalytically hdrogenated at high temperature andpressure, to form hydrocarbons, princi-.

pally C -C alkanes. The resulting hydrocarbons are next oxidizedcatalytically by steam to form the corresponding alcohols, also at hightemperature and pressure.-

The hydrogenation reactor is specially constructed, having the catalystimpregnated in porous, concentric ceramic cylinders, contained in asteel shell. The purified carbon is combined with naphthalene,comprising about 3-10 percent by weight of the charge, and charged intothe reactor, in combination with part of the catalyst, com-. prisingabout 2 percent of the charge. A porous, catalystimpregnated ceramicstrainer is provided at the bottom to hold the charge and to distributethe hydrogen, charged into the bottom of the reactor. Temperature andpressure;

are raised gradually to about 500 C. and 1000 atm, or higher dependingupon the desired end product and reaction time. Residence time duringhydrogenation is about 2-3 hours. The hydrogenation catalyst comprisesabout 15-20 percent nickel, 15-20 percent cobalt molyb- 15-20 percentruthenium and 45-55 percentv date, aluminum.

The hydrogenated products are charged, still under pressure, to the topof an oxidation reactor, which may be constructed in the same manner asthe first reactor. Steam rous, ceramic material. The oxidation reactionproceeds at about BOO-550 C. and 400-500 atm.

The oxidation product is preferably charged into a reactor-distillingretort, also containing the same oxidation catalyst impregnated inporous ceramicmate'rial. There the oxidation reaction is completed, andthe product alcohol is distilled and purified. In order to facilitatethe' distillation, the interior ceramic cylinder is provided with aseries of perforated horizontal plates up the length of the retort. Theproduct alcohols are removed from the top of the reactor retort,condensed and recovered.

' The catalysts employed in the present process maybe reactivated, asthe need arises, by heating in the absence of hydrocarbons to'l500-1600"C.

The invention will be better understood with reference to the attacheddrawing, "which shows equipment suitable for carrying out the presentprocess, and preferred construction details of the reactors employed.

A mixture of 3-10 percent naphthalene and purified carbon is ground tovery fine powder and the whole mass is further mixed with a combinedcatalyst (one part nickel, one part cobalt molybdate, one partruthenium, and three parts alumina) which comprises about 2 percent ofthe whole mass. The whole mixed mass is then charged into thehydrogenation reactor 10. The reactor chamber 10 is made of l /z-inchsteel cylinder 12, 6 feet in diameter and 24 feet long. The verticalreactor is supported with heavy steel framework (not shown) and coatedwith a mixture of manganese dioxide, potters clay, pulverized brick, anddolomite, and lined with refractory bricks. About two-thirds of thelength of the reactor is surrounded by furnace 14, which is equippedwith a device 16 to trap all the combustion products as the furnace 14is being fired. The reactor chamber 10 is lined with a ceramic layer 18.The ceramic layer is porous and contains impregnated catalyst. It iscomposed of three parts granulated firebricks, three parts washedsilica, one part slaked lime, one part portland cement, and to percentof the whole mass is added potassium oxide. The whole mass is mixed withenough amount of water to compose a concrete aggregate, and the concreteaggregate is dosed with a catalytic mixture of one part nickel oxide,one part cobalt molybdate, one part ruthenium, and three parts metallicaluminum powder. The catalyst constitutes about 3-5 percent of the wholeconcrete aggregate. However, before the catalyst mixture is introducedor mixed with the concrete aggregate the molders for the ceramic liningmust be made ready, for upon mixing the catalyst mixture, the concreteaggregate will form a highly porous (foamy) dough. When the ceramic hasproperly set, it is dipped into a solution of -20 percent nickelacetate, after which the ceramic is dried. When completely dried, it isfired to 1,500 C. In lining the ceramic, a mortar made of one part lime,one part portland cement, three parts dolomite (calcined), and fiveparts washed silica is employed. When the whole lining construction 18has set, it is again fired or heated to about 1,600" C. The top of thereactor is also lined with the same ceramic construction 20, and curedto activate the catalyst mixture. At the bottom of the reactor 10, astrainer 22, of the same ceramic construction, containing multipleperforations 23, is incorporated. The reactor 10 is provided with awithdrawal outlet 24 at the bottom and a mechanical charging means 26 atthe top. The reactor 10 is equipped with thermometer and pressure guageand an agitator-grinder (not shown) to emulsify the liquidzed carbon inthe strainer cylinder 22. Extending upwardly from strainer 22 andconcentric to liner 18 is a ceramic cylinder 28 of about 6 inch thickand 4 feet diameter with structural reinforcement made of nickel-platedaluminum bars (not shown), extending the length of the interior of thereactor steel cylinder. The ceramic cylinder 28 also contains the mixedcatalyst, so its construction and composition are similar to theceramics lining 18 of the steel cylinder reactor 10. This cylinderserves a dual purpose, first as a catalyst support, and second as astrainer. Consequently, the cylinder 28 contains minute perforations(not shown) in addition to the concrete pores.

The interior of the furnace 14 is lined with fire-brick 30, and containscoiled 4-inch pipes 32 filled with water from line 31 for the evolutionof steam from line 33. Besides the reactor, another steel cylinder 16 ofthe same size and thickness but without the ceramic lining (not shown)may be provided to contain the combustion gases evolved from thefurnace. This steel cylinder which will contain CO and CO, is lined withthe ashless charcoal rammed and tamped with coal tar and baked toconvert .4 most of the CO to CO. The furnace 14 is fired with oxygen tosupplement atmospheric air through line 35; and the gases in thiscylinder are recycled to the furnace via line 34. At the bottom of thereactor cylinder 10 is fitted the inlet 36 for hydrogen with properinlet stop-cock valve (not shown).

The ground mixture of pure carbon, naphthalene, and mixed catalyst ischarged into the hydrogenation reactor 10 just described. Hydrogen ischarged into its inlet 36 and heated to about from 150-500 C. gradually,with an increasing pressure of from to 1,000 atmospheres. Samples arewithdrawn from time to time to determine the extent of hydrogenation. Ifthe sample material withdrawn is still black with some specks ofunreacted charcoal, hydrogenation has to be carried on further. Whenhydrogenation is completed, however, the sample material is darkbrownish-black and greasy to the touch. The completely hydrogenated purecarbon is then transferred via line 38 to the oxidation reactor 40, andintroduced or charged at the top of the reactor in spray-jet form underpressure of about 1,000 atm. and 45 degrees tangent to the sides of thereactor chamber.

In the hydrogenation reactor 10, the carbon is hydrogenated to formhydrocarbons, principally paraffins of C -C and the naphthalene ishydrogenated to form tetrahydronaphthalene or other saturatedhydrocarbons. The resulting Tetralin (tetrahydronaphthalene) is aneffective solvent for the purified pulverized carbon, and synergizes therapid hydrogenation of the carbon. As As Tetralin is itself unsaturatedit may be hydrogenated further under the high temperature and highpressure, however, the dissolved purified carbon (ashless charcoal)rapidly hydrogenates to form high molecular weight parafiinichydrocarbons. Methane and ethane are formed at the start of thereaction, When the temperatures and pressures are still low. However, asthe temperature and pressure are raised, high mol. wt. paraflinichydrocarbons are finally formed. When the temperature is raised to1,000l,500 C. and the pressure to 3,0004,000 atmospheres (which willrequire a stronger reactor shell) C C parafins may be obtained, whichare capable of producing high octane gasoline by cracking distillation.

The hydrogenated product is a suitable substitute for crude oil fordiesel engines.

The oxidation reactor 40 is constructed in the same manner as thehydrogenation reactor 10. The catalyst impregnated in the ceramicslining 42 and ceramics cylinder 44 inside the steel cylinder 46comprises four parts zinc oxide, two parts copper, 10 parts chromiumoxide, 10 parts silica, 10 parts potassium oxide, and 10 parts boricoxide. The silica is first ground to fine powder, and the remainingconstituents are also ground and mixed with the silica powder. The wholemixture will constitute about 20 percent of the ceramics to be made forlining 42 and for the ceramics cylinder 44. The interior cylinder 44 isalso provided with minute perforations (not shown). After the propersetting of the ceramic, it is heated to 1,500 C. to activate thecatalyst.

Into the oxidation reactor 40 is charged simultaneously the live steamthrough inlet 48 and the paraffinic hydrocarbons through inlet 50. Thelive steam is supplied to the bottom of the reactor 40 at 45 degreestangent and in the opposite direction to the flow of the hydrocarbons,in order to promote turbulent mixing. Temperature is maintained at450-500 C. and at the pressure of about 400-500 atmospheres the higheralcohols form, although the mixed alcohol product still may containsmall amounts of methyl alcohol. The alcohols are mostly ethyl alcoholbecause of the selectivity of the present catalyst. The mixture ofalcohols is made to pass from outlet 52 through the third reactor 54 forfinal and complete synthesis and condensation of residual materials.

The third reactor 54 is actually both a reactor and a distillationretort. In construction and catalyst composition, reactor 54 is similarto reactor 40, except that the interior ceramic cylinder 56 containsperforated ceramic plates 62, of the same composition, leaving /1, inchperforations 63, in order to promote distillation of the alcoholproduct. The retort reactor 54 is provided with three condensers 58-60.The alcohol enters reactor 54 by inlet 57, and after the reaction iscompleted evolves from reactor 54 via line 64 to storage tanks 66. Thehigher boiling residue is .removed from bottoms line 65. It is, ofcourse, possible to remove a certain fraction at any desired point inthe retort, by conventional means not shown.

The purified alcohols made by the present process may be employed in apollution-free automotive motor fuel, in combination with hydrogenperoxide. The exhaust products of such a motor fuel are substantiallycarbon dioxide and water, and are hence non-polluting.

I claim:

1. A process for the preparation of alcohols from purified carbon, whichcomprises:

combining in a reactor about 3-10 percent naphthalene and 90-97 percentpurified carbon, said purified carbon being material which issubstantially pure and ashless, comprising essentially 99.75 percentcarbon, and contacting said reactants at about 500-1500 C. and 100-3000atm., with hydrogen and a hydrogenation catalyst consisting of about15-20 percent nickel, 15-20 percent cobalt molybdate, 15-20 percentruthenium and 45-55 percent aluminum, to hydrogenate said reactants toform paralfinic hydrocarbons;

contacting said paraffinic hydrocarbons and steam at about 300-550 C.and 400-500 atm. with oxidation References Cited UNITED STATES PATENTS2,250,468 7/ 1941 Cockerille 260-632 C 2,020,671 11/1935 Dreyfus 260-632C 2,847,475 8/1958 Voge et a1. 260-632 C 3,240,698 3/1966 Lesk et al.260-632 C 1,919,108 7/1933 Harrison et al 208-10 3,018,242 1/1962 Gorin208-10 3,505,204 4/1970 Holfman 208-10 3,477,941 11/1969 Nelson 208-103,488,280 1/ 1970 Schulrnan 208-10 3,152,063 10/1964 Schroeder et a1.208-10 JOSEPH E. EVANS, Primary Examiner US. Cl. X.R.

